Pressure-responsive switch



1954 M. BURLINGHAM PRESSURE-RESPONSIVE SWITCH Filed June 17, 1950 INVENTOR MICHAEL BURL/NGHAM BY 4 I TTORNEY United States Patent PRESSURE-RESPONSIVE SWITCH Michael Burlingham, Yonkers, N. Y., assignor to Burgua Corporation, Mineola, N. Y., a corporation of New York Application June 17, 1950, Serial No. 168,710

6 Claims. (Cl. 200-83) This invention relates to a switch mechanism, and more particularly to a pressure-responsive switch mechanism for use in automatically starting an internal combustion engine.

While the mechanism of this invention may be advantageously employed in various locales, it is especially useful in starter systems of automobile internal combustion engines. Accordingly, and by way of example, a preferred and recommended form of the mechanism is described in the ensuing description and illustrated inthe accompanying drawing in connection with a starter arrangement for an automobile engine.

A switching mechanism constructed in accordance with this invention preferably comprises a housing consisting of a horizontal base plate and a hollow closure or dome mounted on the base plate and removably secured thereto by a pair of spring clips. Integral with the base plate is a centrally disposed vertical conduit. The conduit includes an upper portion extending into the housing and a lower portion extending below the housing and adapted to be connected to the intake manifold of an automobile engine. A vertically expansible bellows contained in the housing is coaxial with the conduit, the upper end of which terminates therein. The bellows is hermetically sealed at its lower end to the base plate and at its upper end to a head plate carried by the bellows. The bellows may be made of springy material or if preferred, may be provided with a compression spring which bears at its opposite ends against the base plate and the head plate to normally and yieldingly urge the head plate upwardly, thereby expanding the bellows.

The closure is provided with a pair of inwardly projecting lugs having vertical T-slots for receiving the heads of bolts by which a switch is adjustably positioned within the housing above the bellows ith the aid of bolts or the like. The switch is preferably of the type having separate on and oil actuators, although a single actuator switch may he used if opening and closing occur in different positions of the actuator. Excellent results have been achieved by the use of a' reset micro-switch having first and second plungers for respectively closing and opening the switch. The first plunger projects downwardly toward the head plate, while the second plunger extends" upwardly beyond the confines of the switch. The first plunger is aligned with a first adjustable actuating member or screw carried by the head plate. The second plunger is aligned with a second adjustable actuating member or screw carried by a bracket secured to the head plate in spaced relation to the first member. The parts are so arranged that the compression spring normallv' moves the head plate and the first member u wardly to actuate the first element so as to close the switch, thereby placing the switch in active service.

The bellows is contracted, whereby the head plate moves downwardly against the action of the compression spring, in response to sutficient vacuum created in the conduit by operation of the engine, thereby moving the first member out of engagement with the first plunger and then causing the second member to engage and actuate the second plunger so as to open the switch. This places the switch out of active service.

It is a primary object of the invention to provide an improved fluid pressure-responsive switch mechanism which will open at one pressure and will close at another pressure.

It is a further object to provide an improved pressureresponsive switch mechanism for use in the starting s'ystern of an internal combustion engine.

Another object of the invention is to provide a starting mechanism of the character indicated that automatically places the starter of an automobile engine in service if the engine becomes stalled.

A further object of the invention is to provide a pressure-responsive starter mechanism that is simple, sturdy and compact in design and that is reasonable in manufacturing and installation costs.

A still further object of the invention is to provide a mechanism of the character described that is adapted to perform its intended functions in an efiective and trouble-free manner.

The enumerated objects, as well as additional objects, together with the advantages obtainable by the practice of this invention, will be readily apparent to persons skilled in the art upon reference to the following detailed description, taken in conjunction with the annexed drawing, which respectively describe and illustrate a mechanism constructed in accordance with the invention.

In the drawing:

Figure 1 is a view partly diagrammatic and illustrating a switch mechanism embodying this invention, operatively associated with an automobile internal combustion engine and a combined ignition and starter system for the engine;

Figure 2 is a view of the switch mechanism partly in central vertical cross section;

Figure 3 is a view taken along line 3-3 of Figure 2; and

Figure 4 is a view taken along staggered line 4-4 of Figure 2.

Referring now to the drawing wherein like reference numerals denote corresponding parts throughout the several views, a preferred and recommended switch mechanism construction is generally indicated by numeral 5 and comprises a housing consisting of a circular support or base plate 6 having an annular peripheral recess 7 and a hollow closure or dome 8 having an open end that registers with the annular recess. The closure 8 may be provided with a small bleeder opening 8' to expose the interior thereof to the atmosphere. The closure 8 is provided with pairs of oppositely disposed bosses 9 that support pins 10. Pivotally connected to each pin is a spring clip 11 for readily securing the closure to the base plate and permitting speedy removal of the closure, as required. Integral with base plate 6 and extending thereabove and therebelow is a vertical conduit 12 externally threaded at its lower end, as indicated at 13. The conduit 12 is provided with a port 18 of small diameter for a purpose to be described.

A bellows 14 is coaxial with conduit 12 and is hermetically sealed at its lower end to the base plate. The bellows includes a hermetically sealed head plate 15 which is tapped centrally to receive an adjustable actuating member or screw 16. At the time of assembly,

screw 16 is adjusted as required and may, if desired, be maintained in adjusted position by soldering. Within the bellows and also coaxial with the conduit there may he provided a compression spring 17 which, as shown in Figure 3. bears at its opposite ends against the base plate the head plate to normally and yieldingly urge the bellows into expanded position (Figure 3) in the event the bellows are made of a material having insufiicient inherent springiness. The upper extension of conduit 12 may be made of such length as to serve as a stop for the head plate 15, to prevent excessive collapse of the bellows. An upstanding bracket 20 has a flange 21 for attachment to head plate 15 by a rivet 22 or other means known to the art. The bracket is formed at its upper end with a laterally disposed L-shaped arm 23 that carries a second adjustable actuating member or screw 24 at its free end.

A pair of spaced lugs 25 is formed integral with and projects laterally inwardly of closure 8 (Figure 4). These lugs are provided with vertical T-slots 26 that are parallel to each other and adapted to receive the head 27 and a portion of the shank of corresponding bolts 28 for adiustably securing a switch 30 to the lugs with the aid of lock washers 31 and nuts 32. As illustrated. switch 30 is positioned above bello s 14 and intermediate actuating members 16 and 24. The switch is of the reset microswitch type and includes a pair of plungers, namely, a reset or on plunger 33 aligned with member 16 and adapted, upon actuation, to close the switch, and an ofl plunger 34 aligned with member 24 and adapted, upon actuation by member 24, to open the switch. The micro-switch is provided with a pair of binding posts 35 and 36 which are respectively connected by conductors 37 and 38 to corresponding posts 39 and 40 that are carried by closure 8.

As is indicated in Figure l, conduit 12 is adapted to be connected by a union 41 to a conduit 42 that communicates with an intake manifold 43 of an internal combustion engine 44, which, for purposes of illustration, may be of the type employed in automotive vehicles. The engine is provided with a conventional starter device 45. V

The arrangement shown in Figure 1 includes an electrical system that consists of a plurality of series circuits, all energized by a battery 46. Current furnished by the battery is transmitted to an induction coil 47 by way of conductors 48 and 49, an ignition switch 50, and conductors 51 and 52, in the order named. Battery current is supplied to a standard starter relay 53 through conductors 48 and 49, switch 50, conductors 51 and 54, binding post 39, conductor 37 (Figure 3), microswitch 30, conductor 38, binding post 40, and conductor 55. At such times as relay 53 is in active service, battery 46 energizes starter through a circuit comprising conductors 48 and 56, relay 53, and conductor 57.

For the purpose of briefly outlining the mode of operation of the illustrated embodiment of the invention, it is first assumed that the parts are in the relative position shown in the drawing with ignition switch open and engine 44 at rest. Under these conditions, bellows 14 is expanded due to the action of compression spring 17, head plate 15 being at its elevated position so that screw 16 has urged plunger 33 upwardly to on position, closing micro-switch 30.

To start the engine, ignition switch 50 is closed. This permits battery current to flow throu h conductors 48 and 49, ignition switch 50, conductors 51 and 54, microswitch 30 and conductor 55 to relay 53, actuating the relay so that battery current flows through conductors 48 and 56, relay 53 and conductor 57 to starter 45, thereby energizing the starter and turning the engine to start the same. o eration of the engine, vacuum is created in manifold 43. This causes contraction of the bellows, moving head plate 15 and screw 16 downwardly out of engagement with plunger 33 against the action of spring 17. Inasmuch as the micro-switch is of the reset type, it remains closed until such time as screw 24 moves downwardly so as to actuate plunger 34 to open the switch. At su h time as the en ine is operating at idling speed, suflicient vacuum is created in the bellows to move head plate 15 and, therefore, bracket 20 downwardly to an extent th t screw 24 contacts and moves plunger 34 downwardlv. thereby opening switch 30 to place the same out f service.

When i nition switch 50 is again opened. cuttin otf the en ine. the de ree of vacuum in the bellows is reduced ermi ting com ressi n spring 17 to return bead late 15 and screw 16 to the posi ion shown in Fi ure 3. therebv resetting the micro-switch to clo ed position. n the event that the en ine becomes stalled durin e tion. the rednr-tion in vacuum in the i take man ld and in he e s also permits sprin 17 to actu e p un er 33 and it the i nition s i h 50 is still c d. t restart he en ine. The small di me er port 18 intr d es a (ielaV in the eXDansi Wl of he be l s to v id instantaneous clo in f the icro-s it h whi h mi h be caused bv a hanlrfire or sudden excessive loadi the ermine in operation. Also. the delay thus cau e will e m the rter motor to come to rest in case nt F lse, star in at the en ine.

t will be a ent that screw 33 mav be so adinsted th hi h rnani d pressures incident to heavv loading o he en ine w l n t accidentallv ener ize the s rt r. The Starter in the illustrated constructi n is e er iz d only hen the rnanitold pressure is atm spheric. but Once it is ac u ted. it remains in o e a i n until the manttnid pressure drops to a point indicating normal eration nt the en ine.

Arnmw the outstandin advantages and features of the present invention when adapted to a startin system are: the elimination of conventional starter buttons as the In the course of engine starting and continued engine is started by merely closing the ignition switch; prompt and automatic restarting of the engine in the event of stalling; prevention or accidental operation of the starter prior to closing the ignition switch or while the engine is in normal operation.

In the starter system, herein described, the parts are so arranged that micro-switch 30 is opened at low fluid pressure and closed at high pressure. It is recognized that my switch mechanism may be used in systems that may require reversal of opening and closing of the micro-switch. In such cases, the micro-switc may be of the type that closes when the bellows is contracted and is reset into open position when the bellows is expanded.

From the foregoing, it is believed that the construction, operation, and advantages of my present invention will be readily comprehended by persons skilled in the art. It is to be clearly understood, however, that various changes in the apparatus set forth above may be made without departing from the scope of the invention, it being intended that all matter contained in the description or shown in the drawing shall be interpreted as illustrative only and not in a limiting sense.

I claim:

1. In a mechanism of the character described, a support, an electric switch mounted on the support and including first and second movable elements for respectively closing and opening the same, actuating means for alternately placing the switch in closed and open positions, said actuating means comprising a first member aligned with and independent of the first element for moving the same in a direction to close the switch and a second member spaced from the first member, said second member being aligned with and independent of the second element for moving the same in a direction to open the switch, resilient means normally biasing the actuating means in one direction to place the switch in one of said positions, a conduit secured to the support, and pressure-sensitive means biasing the actuating means in a reverse direction against the action of the resilient means in response to variations in fluid pres ure in the conduit to place the switch in the other of said ositions.

2. In a mechanism of the character described. a sup port. an electric switch mounted on the support. a bellows carried by the support and including a movable head plate, first and second members secured to and mov ble with the head plate for actuating the switch to res ectivelv close and open the same, said bellows including resilient means normally ur ing the head pl te in one direction to move the first member to s itch-closin osition. and a conduit communicating with the interior of the bellows. said head plate being mo able in a reverse direction against the acti n of the resilient means in response to variations in fluid pressure in the co duit to corresp ndingly move the second member to switch-opening position.

3. In a me hanism of the character described. a support. an electric switch mounted on he supp rt. a bel ws c rried by the support and including a mov ble he d plate. first and second mem ers secured o and m v b e with the head plate for ctuating the s i ch to e n tely place the same in closed and open positions. s id bel o s includin resi ient means n rm llv ur ing the head pl te in one direction to expand the bellows and m ve the first member to actuate the s it h to one of s id ositions. and a con ui communicatin wi h the int ri r of the be l s. said l ows bein con r cte and e he d pl e bein mov e in a reverse direction a ain t the a ion o he re ilient rn ns the e f in re nse to a drop in fluid pressure in the c n ui to m ve he e ond r ber to actuate the switch into the other of said positions.

4, Tn a me hanism of the charac er describ d, a simnnrh an electric switch mounted nn the, gunnort a bellows c rrie bv the supp rt and includino a mov ble head D and second members secured to an mova le wi h the head p te for ctu tin the switch to r telv place he same in closed and o en posi ions. s id b ll ws includin resilient means normall ur ing the head pl te in one direc i n to expa d the bellows an m ve the fi st me er to a ua e the s i h to e f said positions. and a conduit nnmmnnicafintz with the int ri r of the s. said ws being contra ted and he head plate being movable in a reverse direction a ainst the action of the resilient means thereof in response to a drop in fluid pressure in the conduit to move the second member to actuate the switch into the other of said positions, said switch including first and second plungers aligned respectively with the first and second members and adapted to be actuated by the members to alternately close and open the switch, the first plunger being disposed to the side of the switch adjacent the head plate and the second plunger being disposed to the side of the switch remote from the head plate, the first and second members being spaced from each other and adjustable relative to the head plate.

5. In a mechanism of the character described, a housing comprising a base and a closure attached to the base, a bellows secured to the base and positioned within the housing, said bellows including a movable head plate, a first member secured to and projecting beyond the exterior of the head plate, a second member mounted on and positioned exterior the head plate in spaced relation to the first member, an electric switch supported in the housing in spaced relation to the bellows, said switch being adjustable relative to the bellows and including a first plunger aligned with the first member for effecting closing of the switch and a second plunger aligned with the second member for efiecting opening of the switch, said bellows including resilient means normally urging the head plate in one direction to expand the bellows and move the first member into engagement with the first plunger to actuate the switch into closing position, and a conduit communicating with the interior of the bellows, said bellows being contracted and the head plate being movable in a reverse direction against the action of the resilient means in response to variations in fluid pressure in the conduit to move the first member out of engagement with the first plunger and the second member into engagement with the second plunger to open the switch.

6. A mechanism in accordance with claim 5 wherein the switch is secured to the closure, the resilient means comprises a compression spring wholly within the bellows and bearing at its opposite ends against the base and the head plate, the first member and first plunger being disposed to the side of the switch adjacent the head plate, and the second plunger and second member being dlisposed to the side of the switch remote from the head p ate.

References Cited in the file of this patent UNITED STATES PATENTS 

